1. Field of the Invention
This invention relates to valves and in particular to a fluid control valve and method of making same.
2. Description of the Prior Art
It is known in the art to provide fluid control valves each comprising a valve body structure having a fluid flow passage therethrough and first sealing surface means, and a closure structure for controlling fluid flow through the passage with the closure structure having a second sealing surface means adapted to engage the first sealing surface means to shut off fluid flow through the associated valve.
However, some of the known fluid control valves are often used to control flow of fluids wherein a particular fluid is at such a temperature that there is a tendency to reduce or weaken the structural integrity of its associated valve. Others of such known fluid control valves are used to control fluids containing particles, or the like, which tend to accumulate or build up on the sealing surface means comprising the valve body structure and/or the valve closure structure of the associated valve. The accumulated particles on such sealing surface means tend to impair the sealing action of the associated component and hence the sealing action of the overall valve or tend to cause premature failure of the associated component and/or any component cooperating or associated therewith due to the abrading tendency of the material accumulated on the associated sealing surface means. Accordingly, the control valves mentioned have the indicated deficiencies.
In an effort to solve the above-mentioned problems various valves have been proposed heretofore. In particular, one such valve, in the form of a butterfly valve, is disclosed in U.S. Pat. No. 4,289,296. The valve of this patent utilizes a so-called bidirectional axially pliant pressure assisted seat.
Another previously proposed valve, also in the form of a butterfly valve, employs a closure member which has a hollow cavity between two roughly parallel facing cup-shaped discs comprising such closure member. The cavity is adapted to receive a fluid therein for heating the entire disc to prevent any accumulation on the sealing surface thereof of any material contained in the fluid being controlled by the valve.
Finally, other previously proposed valves have been provided with jackets completely therearound for the purpose of either heating or cooling same, as desired, to thereby control accumulations on the sealing surfaces thereof and/or control the structural integrity of such valves.
However, the valves proposed heretofore, including each of the valves specifically mentioned above, are basically deficient in that the control of the temperatures of the sealing surface means thereof is not provided with optimum efficiency.